(1) Field of the Invention
The invention relates to a process of making a shaped product consisting of aluminum or an aluminum alloy, comprising the steps of producing an intermediate object by extrusion or rolling and reshaping the intermediate object into the shaped product.
(2) Description of the Related Art
Such a process is generally known and is used for producing different types of tubing such as wrapped tubes, folded tubes or so-called welded tubes.
For a number of such shaped products it is required to interconnect different portions of the shaped product in order to obtain a sealed construction, such as e.g. required for tubing, or to obtain the required strength such as e.g. required in folded tubes. This is commonly done by brazing. If such connection is required it becomes necessary to at least provide the surface of one portion to be brazed with a flux coating.
All known flux coatings, however, have the disadvantage that they have to be applied after the reshaping of the intermediate object into the shaped product. These known flux coatings are generally brittle and/or lack the adherence to the aluminum surface to withstand the deformation forces while reshaping the intermediate object. Therefor the common flux coating will partly spring off from the aluminum surface while reshaping, and this especially in these areas where deformation occurs.